1. Field of the Invention
The present invention relates to an image processing apparatus and method for directly receiving an electronic document and subjecting the document to image processing.
2. Description of the Related Art
Owing to the diversification of application software and operating systems in recent years, print rendering instructions have become more complex and this has placed an increasing load on printing devices for the purpose of rendering and image processing. A rendering method based upon scan line rendering is in use in order to process complex rendering instructions and high speed.
Scan line rendering is a technique for extracting the outlines of objects, removing edge overlap between objects and applying sort processing to edge columns from which overlap has been eliminated (see Japanese Patent Laid-Open No. 10-177657).
In case of data in which rendered objects are overlapping at the same location or data in which rendered objects have been rendered densely with respect to nearby areas, a heavy load is imposed upon sort processing and processing takes a very long time. A technique that removes character-object overlap has been proposed as a measure for dealing with overlapping objects (see Japanese Patent Laid-Open No. 2011-002977).
With this technique for removing overlap character-object overlap, if character data has been rendered successively, the solution involves sensing edge overlap during rendering and deleting unnecessary data of lower order.
However, since an object such as a graphic or line is composed of one object and a combination of two or more edges, deletion is difficult. Further, in a case where graphic objects are overlapping, judgments cannot be made based upon only one edge and it is necessary to perform determination and deletion for every combination of edges. Such determination and deletion is difficult.